April 2013 - AFMA

Control of E. coli, Salmonella
and other potential pathogens
By Dr Peter Theobald, Addcon Europe GmbH, Germany
Contamination of animals with
pathogenic bacteria creates
enormous social and economic
costs worldwide. The annual
costs of Salmonella alone to the
UK economy are more than 46 million British
pounds, with estimated 2,8 billion euro
losses across the European Union (World
Health Organisation, 2005). New management
and dietary strategies to counteract
intestinal pathogens in animal production
are therefore of great interest.
Preventing the spread of E. coli and Salmonella
to the consumer requires special
control measures during slaughter and
processing. Improving gut health has been
shown to be effective against intestinal
pathogens (Eidelsburger et al., 1992). While
biosecurity and hygiene in the feed mill and
on the farm are essential, the acidification of
feed ingredients or finished feeds with organic
acids also offers considerable benefits
in E. coli and Salmonella control.
Feed acidification is not only effective
within the feed – possibly its biggest benefit
occurs within the pig itself. In different European
case studies diformates have proven
their high effectiveness to decrease potential
pathogens in monogastric farm animals.
Literature review
The positive effect of organic acids and their
salts in preserving feed from microbial and
fungal destruction is known for decades.
Also, the positive effect on improved buffering
capacity of the diet with an increased
digestibility of nutrients, especially protein
digestibility and thereby reducing pathogen
colonisation, is often described (Eidelsburger
et al., 1992; Kirchgessner et al., 1992;
Eidelsburger & Kirchgessner, 1994; Freitag,
2007).
Strauss and Hayler (2001) showed under
in vitro conditions the strong antibacterial
effects for formic acid, in comparison to
propionic and lactic acids. Considering the
mode of action of organic acids, it is a precondition
to have contact between the acid
Table 1: The effect of different types of feed additives in weaners
Parameter Control K-diformate (KDF)
(1,2%)
Colistin
(120 ppm)
ZnO
(2500 ppm)
Feed intake (g/day) 760 787 791 778
Weight gain (g/day) 543ab 565a 565a 537b
FCR# 1,40a 1,40a 1,40a 1,45b
Diarrhoea (%) 39,6a 0,7b 14,6c 12,5c
Means in rows bearing unlike superscripts differ significantly (P